Make the vendor name optional in the -m flashrom parameter when there's only one board name that matches

The full syntax still works, and is required when two vendors have
boards with the same names.

Corresponding to flashrom svn r190 and coreboot v2 svn r3082.

Signed-off-by: Peter Stuge <peter@stuge.se>
Acked-by: Stefan Reinauer <stepan@coresystems.de>
diff --git a/flashrom.8 b/flashrom.8
index 3251738..287b7f7 100644
--- a/flashrom.8
+++ b/flashrom.8
@@ -40,11 +40,11 @@
 .B "\-e, \-\-eend" <addr> 
 Exclude end postion (obsolete).
 .TP
-.B "\-m, \-\-mainboard" <vendor:part>
+.B "\-m, \-\-mainboard" <[vendor:]part>
 Override mainboard settings. This option is needed for some mainboards,
 see the
 .B flashrom
-README for a list.
+README for a list. The vendor is not required when the board name is unique.
 .TP
 .B "\-f, \-\-force"
 Force write without checking whether the ROM image file is really meant